import {CockroachDriver} from "../driver/cockroachdb/CockroachDriver";
import {QueryBuilder} from "./QueryBuilder";
import {ObjectLiteral} from "../common/ObjectLiteral";
import {EntityTarget} from "../common/EntityTarget";
import {Connection} from "../connection/Connection";
import {QueryRunner} from "../query-runner/QueryRunner";
import {SqlServerDriver} from "../driver/sqlserver/SqlServerDriver";
import {PostgresDriver} from "../driver/postgres/PostgresDriver";
import {WhereExpressionBuilder} from "./WhereExpressionBuilder";
import {Brackets} from "./Brackets";
import {UpdateResult} from "./result/UpdateResult";
import {ReturningStatementNotSupportedError} from "../error/ReturningStatementNotSupportedError";
import {ReturningResultsEntityUpdator} from "./ReturningResultsEntityUpdator";
import {MysqlDriver} from "../driver/mysql/MysqlDriver";
import {OrderByCondition} from "../find-options/OrderByCondition";
import {LimitOnUpdateNotSupportedError} from "../error/LimitOnUpdateNotSupportedError";
import {MissingDeleteDateColumnError} from "../error/MissingDeleteDateColumnError";
import {OracleDriver} from "../driver/oracle/OracleDriver";
import {UpdateValuesMissingError} from "../error/UpdateValuesMissingError";
import {EntitySchema} from "../entity-schema/EntitySchema";
import { TypeORMError } from "../error";

/**
 * Allows to build complex sql queries in a fashion way and execute those queries.
 */
export class SoftDeleteQueryBuilder<Entity> extends QueryBuilder<Entity> implements WhereExpressionBuilder {

    // -------------------------------------------------------------------------
    // Constructor
    // -------------------------------------------------------------------------

    constructor(connectionOrQueryBuilder: Connection|QueryBuilder<any>, queryRunner?: QueryRunner) {
        super(connectionOrQueryBuilder as any, queryRunner);
        this.expressionMap.aliasNamePrefixingEnabled = false;
    }

    // -------------------------------------------------------------------------
    // Public Implemented Methods
    // -------------------------------------------------------------------------

    /**
     * Gets generated SQL query without parameters being replaced.
     */
    getQuery(): string {
        let sql = this.createUpdateExpression();
        sql += this.createOrderByExpression();
        sql += this.createLimitExpression();
        return sql.trim();
    }

    /**
     * Executes sql generated by query builder and returns raw database results.
     */
    async execute(): Promise<UpdateResult> {
        const queryRunner = this.obtainQueryRunner();
        let transactionStartedByUs: boolean = false;

        try {

            // start transaction if it was enabled
            if (this.expressionMap.useTransaction === true && queryRunner.isTransactionActive === false) {
                await queryRunner.startTransaction();
                transactionStartedByUs = true;
            }

            // call before updation methods in listeners and subscribers
            if (this.expressionMap.callListeners === true && this.expressionMap.mainAlias!.hasMetadata) {
                await queryRunner.broadcaster.broadcast("BeforeUpdate", this.expressionMap.mainAlias!.metadata);
            }

            // if update entity mode is enabled we may need extra columns for the returning statement
            const returningResultsEntityUpdator = new ReturningResultsEntityUpdator(queryRunner, this.expressionMap);
            if (this.expressionMap.updateEntity === true &&
                this.expressionMap.mainAlias!.hasMetadata &&
                this.expressionMap.whereEntities.length > 0) {
                this.expressionMap.extraReturningColumns = returningResultsEntityUpdator.getSoftDeletionReturningColumns();
            }

            // execute update query
            const [sql, parameters] = this.getQueryAndParameters();

            const queryResult = await queryRunner.query(sql, parameters, true);
            const updateResult = UpdateResult.from(queryResult);

            // if we are updating entities and entity updation is enabled we must update some of entity columns (like version, update date, etc.)
            if (this.expressionMap.updateEntity === true &&
                this.expressionMap.mainAlias!.hasMetadata &&
                this.expressionMap.whereEntities.length > 0) {
                await returningResultsEntityUpdator.update(updateResult, this.expressionMap.whereEntities);
            }

            // call after updation methods in listeners and subscribers
            if (this.expressionMap.callListeners === true && this.expressionMap.mainAlias!.hasMetadata) {
                await queryRunner.broadcaster.broadcast("AfterUpdate", this.expressionMap.mainAlias!.metadata);
            }

            // close transaction if we started it
            if (transactionStartedByUs)
                await queryRunner.commitTransaction();

            return updateResult;

        } catch (error) {

            // rollback transaction if we started it
            if (transactionStartedByUs) {
                try {
                    await queryRunner.rollbackTransaction();
                } catch (rollbackError) { }
            }
            throw error;

        } finally {
            if (queryRunner !== this.queryRunner) { // means we created our own query runner
                await queryRunner.release();
            }
        }
    }

    // -------------------------------------------------------------------------
    // Public Methods
    // -------------------------------------------------------------------------

    /**
     * Specifies FROM which entity's table select/update/delete/soft-delete will be executed.
     * Also sets a main string alias of the selection data.
     */
    from<T>(entityTarget: EntityTarget<T>, aliasName?: string): SoftDeleteQueryBuilder<T> {
        entityTarget = entityTarget instanceof EntitySchema ? entityTarget.options.name : entityTarget;
        const mainAlias = this.createFromAlias(entityTarget, aliasName);
        this.expressionMap.setMainAlias(mainAlias);
        return (this as any) as SoftDeleteQueryBuilder<T>;
    }

    /**
     * Sets WHERE condition in the query builder.
     * If you had previously WHERE expression defined,
     * calling this function will override previously set WHERE conditions.
     * Additionally you can add parameters used in where expression.
     */
    where(where: string|((qb: this) => string)|Brackets|ObjectLiteral|ObjectLiteral[], parameters?: ObjectLiteral): this {
        this.expressionMap.wheres = []; // don't move this block below since computeWhereParameter can add where expressions
        const condition = this.getWhereCondition(where);
        if (condition)
            this.expressionMap.wheres = [{ type: "simple", condition: condition }];
        if (parameters)
            this.setParameters(parameters);
        return this;
    }

    /**
     * Adds new AND WHERE condition in the query builder.
     * Additionally you can add parameters used in where expression.
     */
    andWhere(where: string|((qb: this) => string)|Brackets|ObjectLiteral|ObjectLiteral[], parameters?: ObjectLiteral): this {
        this.expressionMap.wheres.push({ type: "and", condition: this.getWhereCondition(where) });
        if (parameters) this.setParameters(parameters);
        return this;
    }

    /**
     * Adds new OR WHERE condition in the query builder.
     * Additionally you can add parameters used in where expression.
     */
    orWhere(where: string|((qb: this) => string)|Brackets|ObjectLiteral|ObjectLiteral[], parameters?: ObjectLiteral): this {
        this.expressionMap.wheres.push({ type: "or", condition: this.getWhereCondition(where) });
        if (parameters) this.setParameters(parameters);
        return this;
    }

    /**
     * Adds new AND WHERE with conditions for the given ids.
     */
    whereInIds(ids: any|any[]): this {
        return this.where(this.getWhereInIdsCondition(ids));
    }

    /**
     * Adds new AND WHERE with conditions for the given ids.
     */
    andWhereInIds(ids: any|any[]): this {
        return this.andWhere(this.getWhereInIdsCondition(ids));
    }

    /**
     * Adds new OR WHERE with conditions for the given ids.
     */
    orWhereInIds(ids: any|any[]): this {
        return this.orWhere(this.getWhereInIdsCondition(ids));
    }
    /**
     * Optional returning/output clause.
     * This will return given column values.
     */
    output(columns: string[]): this;

    /**
     * Optional returning/output clause.
     * Returning is a SQL string containing returning statement.
     */
    output(output: string): this;

    /**
     * Optional returning/output clause.
     */
    output(output: string|string[]): this;

    /**
     * Optional returning/output clause.
     */
    output(output: string|string[]): this {
        return this.returning(output);
    }

    /**
     * Optional returning/output clause.
     * This will return given column values.
     */
    returning(columns: string[]): this;

    /**
     * Optional returning/output clause.
     * Returning is a SQL string containing returning statement.
     */
    returning(returning: string): this;

    /**
     * Optional returning/output clause.
     */
    returning(returning: string|string[]): this;

    /**
     * Optional returning/output clause.
     */
    returning(returning: string|string[]): this {

        // not all databases support returning/output cause
        if (!this.connection.driver.isReturningSqlSupported())
            throw new ReturningStatementNotSupportedError();

        this.expressionMap.returning = returning;
        return this;
    }

    /**
     * Sets ORDER BY condition in the query builder.
     * If you had previously ORDER BY expression defined,
     * calling this function will override previously set ORDER BY conditions.
     *
     * Calling order by without order set will remove all previously set order bys.
     */
    orderBy(): this;

    /**
     * Sets ORDER BY condition in the query builder.
     * If you had previously ORDER BY expression defined,
     * calling this function will override previously set ORDER BY conditions.
     */
    orderBy(sort: string, order?: "ASC"|"DESC", nulls?: "NULLS FIRST"|"NULLS LAST"): this;

    /**
     * Sets ORDER BY condition in the query builder.
     * If you had previously ORDER BY expression defined,
     * calling this function will override previously set ORDER BY conditions.
     */
    orderBy(order: OrderByCondition): this;

    /**
     * Sets ORDER BY condition in the query builder.
     * If you had previously ORDER BY expression defined,
     * calling this function will override previously set ORDER BY conditions.
     */
    orderBy(sort?: string|OrderByCondition, order: "ASC"|"DESC" = "ASC", nulls?: "NULLS FIRST"|"NULLS LAST"): this {
        if (sort) {
            if (sort instanceof Object) {
                this.expressionMap.orderBys = sort as OrderByCondition;
            } else {
                if (nulls) {
                    this.expressionMap.orderBys = { [sort as string]: { order, nulls } };
                } else {
                    this.expressionMap.orderBys = { [sort as string]: order };
                }
            }
        } else {
            this.expressionMap.orderBys = {};
        }
        return this;
    }

    /**
     * Adds ORDER BY condition in the query builder.
     */
    addOrderBy(sort: string, order: "ASC"|"DESC" = "ASC", nulls?: "NULLS FIRST"|"NULLS LAST"): this {
        if (nulls) {
            this.expressionMap.orderBys[sort] = { order, nulls };
        } else {
            this.expressionMap.orderBys[sort] = order;
        }
        return this;
    }

    /**
     * Sets LIMIT - maximum number of rows to be selected.
     */
    limit(limit?: number): this {
        this.expressionMap.limit = limit;
        return this;
    }

    /**
     * Indicates if entity must be updated after update operation.
     * This may produce extra query or use RETURNING / OUTPUT statement (depend on database).
     * Enabled by default.
     */
    whereEntity(entity: Entity|Entity[]): this {
        if (!this.expressionMap.mainAlias!.hasMetadata)
            throw new TypeORMError(`.whereEntity method can only be used on queries which update real entity table.`);

        this.expressionMap.wheres = [];
        const entities: Entity[] = Array.isArray(entity) ? entity : [entity];
        entities.forEach(entity => {

            const entityIdMap = this.expressionMap.mainAlias!.metadata.getEntityIdMap(entity);
            if (!entityIdMap)
                throw new TypeORMError(`Provided entity does not have ids set, cannot perform operation.`);

            this.orWhereInIds(entityIdMap);
        });

        this.expressionMap.whereEntities = entities;
        return this;
    }

    /**
     * Indicates if entity must be updated after update operation.
     * This may produce extra query or use RETURNING / OUTPUT statement (depend on database).
     * Enabled by default.
     */
    updateEntity(enabled: boolean): this {
        this.expressionMap.updateEntity = enabled;
        return this;
    }

    // -------------------------------------------------------------------------
    // Protected Methods
    // -------------------------------------------------------------------------

    /**
     * Creates UPDATE express used to perform insert query.
     */
    protected createUpdateExpression() {
        const metadata = this.expressionMap.mainAlias!.hasMetadata ? this.expressionMap.mainAlias!.metadata : undefined;
        if (!metadata)
            throw new TypeORMError(`Cannot get entity metadata for the given alias "${this.expressionMap.mainAlias}"`);
        if (!metadata.deleteDateColumn) {
            throw new MissingDeleteDateColumnError(metadata);
        }

        // prepare columns and values to be updated
        const updateColumnAndValues: string[] = [];

        switch (this.expressionMap.queryType) {
            case "soft-delete":
                updateColumnAndValues.push(this.escape(metadata.deleteDateColumn.databaseName) + " = CURRENT_TIMESTAMP");
                break;
            case "restore":
                updateColumnAndValues.push(this.escape(metadata.deleteDateColumn.databaseName) + " = NULL");
                break;
            default:
                throw new TypeORMError(`The queryType must be "soft-delete" or "restore"`);
        }
        if (metadata.versionColumn)
            updateColumnAndValues.push(this.escape(metadata.versionColumn.databaseName) + " = " + this.escape(metadata.versionColumn.databaseName) + " + 1");
        if (metadata.updateDateColumn)
            updateColumnAndValues.push(this.escape(metadata.updateDateColumn.databaseName) + " = CURRENT_TIMESTAMP"); // todo: fix issue with CURRENT_TIMESTAMP(6) being used, can "DEFAULT" be used?!

        if (updateColumnAndValues.length <= 0) {
            throw new UpdateValuesMissingError();
        }

        // get a table name and all column database names
        const whereExpression = this.createWhereExpression();
        const returningExpression = this.createReturningExpression();

        // generate and return sql update query
        if (returningExpression && (this.connection.driver instanceof PostgresDriver || this.connection.driver instanceof OracleDriver || this.connection.driver instanceof CockroachDriver)) {
            return `UPDATE ${this.getTableName(this.getMainTableName())} SET ${updateColumnAndValues.join(", ")}${whereExpression} RETURNING ${returningExpression}`;

        } else if (returningExpression && this.connection.driver instanceof SqlServerDriver) {
            return `UPDATE ${this.getTableName(this.getMainTableName())} SET ${updateColumnAndValues.join(", ")} OUTPUT ${returningExpression}${whereExpression}`;

        } else {
            return `UPDATE ${this.getTableName(this.getMainTableName())} SET ${updateColumnAndValues.join(", ")}${whereExpression}`; // todo: how do we replace aliases in where to nothing?
        }
    }

    /**
     * Creates "ORDER BY" part of SQL query.
     */
    protected createOrderByExpression() {
        const orderBys = this.expressionMap.orderBys;
        if (Object.keys(orderBys).length > 0)
            return " ORDER BY " + Object.keys(orderBys)
                    .map(columnName => {
                        if (typeof orderBys[columnName] === "string") {
                            return this.replacePropertyNames(columnName) + " " + orderBys[columnName];
                        } else {
                            return this.replacePropertyNames(columnName) + " " + (orderBys[columnName] as any).order + " " + (orderBys[columnName] as any).nulls;
                        }
                    })
                    .join(", ");

        return "";
    }

    /**
     * Creates "LIMIT" parts of SQL query.
     */
    protected createLimitExpression(): string {
        let limit: number|undefined = this.expressionMap.limit;

        if (limit) {
            if (this.connection.driver instanceof MysqlDriver) {
                return " LIMIT " + limit;
            } else {
                throw new LimitOnUpdateNotSupportedError();
            }
        }

        return "";
    }

}
